1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

1989 to 1995 ecm switch

Discussion in 'TBI & EFI Conversions' started by Mike Harrington, May 18, 2020.

  1. Mike Harrington

    Mike Harrington Junior Member

    Posts:
    22
    Likes Received:
    3
    Joined:
    Apr 27, 2020
    Location:
    Briggs,Texas
    First Name:
    Mike
    Truck Year:
    1989
    Truck Model:
    K3500
    Engine Size:
    454 7.4
    I've got a 1989 k3500 with manual transmission and it had the Mark IV 454 but I'm putting a 454 from a 1995 into it. I got the computer and wire harness from the 1995 with hopes of just switching my out the ecm but I see that is not possible. Is there a wire harness adapter that would allow me to just switch the ECM out and run the one from the 1995? Or how hard is it to switch out the entire wire harness or is it just easier to get a new chip burned for the original ecm or will the old chip work for the 1995 engine?
     
  2. bucket

    bucket Super Moderator Staff Member

    Age:
    38
    Posts:
    21,279
    Likes Received:
    6,744
    Joined:
    Aug 3, 2010
    Location:
    Usually not in Ohio
    First Name:
    Andy
    Truck Year:
    '77, '78, '79, '84, '88
    Truck Model:
    K5 thru K30
    Engine Size:
    350-454
    The '95 engine should run fine with the original ECM and PROM. Despite being a different generation of 454, the cam and airflow specs are essentially the same between the two.
     
  3. Mike Harrington

    Mike Harrington Junior Member

    Posts:
    22
    Likes Received:
    3
    Joined:
    Apr 27, 2020
    Location:
    Briggs,Texas
    First Name:
    Mike
    Truck Year:
    1989
    Truck Model:
    K3500
    Engine Size:
    454 7.4
    Bucket...but what about the egr? The 1995 454 has an electronic egr and the 1989 had the regular EGR valve and solenoid. How would I convert the wiring harness to the electronic EGR? Do they make an adapter?
     
  4. bucket

    bucket Super Moderator Staff Member

    Age:
    38
    Posts:
    21,279
    Likes Received:
    6,744
    Joined:
    Aug 3, 2010
    Location:
    Usually not in Ohio
    First Name:
    Andy
    Truck Year:
    '77, '78, '79, '84, '88
    Truck Model:
    K5 thru K30
    Engine Size:
    350-454
    Well there I go assuming again. I just assumed that the original intake, tbi, etc were being re-used.

    But why not just use the original setup?
     
    Mike Harrington likes this.
  5. Mike Harrington

    Mike Harrington Junior Member

    Posts:
    22
    Likes Received:
    3
    Joined:
    Apr 27, 2020
    Location:
    Briggs,Texas
    First Name:
    Mike
    Truck Year:
    1989
    Truck Model:
    K3500
    Engine Size:
    454 7.4
    The original setup is a crappy intake that is an actual carburator intake with that adapter to a TBI. The new one is an actual TBI intake. I found an adapter that goes from 2 wire to 5 wire for the egr on eBay I just wonder if it will actually work. https://www.ebay.com/itm/262666546281
     
  6. bucket

    bucket Super Moderator Staff Member

    Age:
    38
    Posts:
    21,279
    Likes Received:
    6,744
    Joined:
    Aug 3, 2010
    Location:
    Usually not in Ohio
    First Name:
    Andy
    Truck Year:
    '77, '78, '79, '84, '88
    Truck Model:
    K5 thru K30
    Engine Size:
    350-454
    Yes, but the TBI specific intake is just as crappy as the older unit with an adapter.

    That ebay adapter may work fine. Iirc, the Painless Performance TBI harness comes with the same adapter for use with the later style egr.
     

Share This Page